The graph above shows the carbon intensity of global energy consumption from 1965 to 2013. Specifically, it shows the amount of carbon emissions (in tons) for every "ton of oil equivalent" consumed in the global economy. Thus, the consumption data includes both carbon intensive sources of energy (coal, gas, oil) and also the less carbon intensive sources (hydro, wind, solar, nuclear, etc.).

The graph shows that global energy consumption decarbonized at a remarkably steady rate from 1965 to the late 1990s. Since then, global energy consumption has become slightly more carbon intensive. In 2013 the carbon intensity of global energy consumption was just about the same as it was in 1991. Since 1999, this metric of carbon intensity has increased by 1.5%. The graph indicates that in the 21st century, whatever gains are being made by low carbon energy technologies, they continue to be equaled or even outpaced by continuing gains in fossil fuels.

To place this analysis in perspective: Cutting global carbon dioxide emissions by 50% (just to pick a round number) while increasing global energy consumption by 50% (another round number) implies a carbon intensity of 0.25 tons carbon per ton of oil equivalent.

For those wanting to explore a little deeper into why this analysis matters for how we might think about climate policies, have a look at this paper in PDF.

The proportion of carbon-free energy consumption is a far more important metric of progress with respect to the challenge of stabilizing carbon dioxide levels in the atmosphere than looking at carbon dioxide emissions. The reason for this is that emissions are a consequence of energy consumption, and the way that we influence emissions is through energy technologies and their use in the economy. So looking directly at energy consumption is a much more direct and relevant way to understand the technological challenge of emissions reductions. From a policy perspective, looking solely at emissions can easily deceive.

In 2013 the proportion of carbon-free energy consumption was just about 13%, representing a continuation of no trend in that measure that has continued for more than 20 years. The measure did tick up from 2012 - from 13.1% to 13.3%, to just about equal to what it was in 1999.

To stabilize atmospheric concentrations of carbon dioxide requires that this proportion exceed 90%, independent of how much energy the world ultimately consumes. But don't take my word for it, do the math yourself. The timing of exceeding that 90% threshold will determine the atmospheric concentration level at which stabilization ultimately occurs.

If the increase in the carbon-free proportion from 2012 to 2013 (of 0.17%) is taken as a trend going forward, then the 90% threshold will be exceeded in the year 2465. Fortunately, linear projections of most anything related to future energy are wrong.

What you should take from this however is that there remains no evidence of an increase in the proportion of carbon-free energy consumption even remotely consistent with the challenge of atmospheric stabilization of atmospheric carbon dioxide. Those who claim that the world has turned a corner, soon will, or that they know what steps will get us around that corner are dreamers or fools. We don't know. The sooner we accept that, the sooner we can design policies more compatible with policy learning and muddling through.

13 June 2014

Last week I had a letter in the Financial Times in which I explained the simple but powerful logic of the Kaya Identity for understanding efforts to reduce carbon dioxide emissions (for some nice discussions see here, here and here). The letter was motivated by a proposal floated by a Chinese academic that China should "cap" its emissions in the near term. I used the logic of the Kaya Identity to conclude:

It should thus not come as a surprise that carbon caps have not led to emissions reductions or even limitations anywhere. China will be no different.

In response, Paul Krugman of the New York Times took the opportunity to show great outrage at my letter, calling me a "concern troll" and "stupid." Powerful argumentation I know. Where there was some substance, Krugman made arguments against claims I did not make.

Any near-term regulation of China's greenhouse gas emissions would likely allow for future emissions growth, a senior government official said on Monday, discounting any suggestion of imminent carbon cuts by the biggest-emitting nation.

Sun Cuihua, deputy director of the climate change office at the National Development and Reform Commission, said it would be a simplification to suggest China would impose an absolute cap on greenhouse gas emissions from 2016.

No decision had yet been taken on a cap and the timing of such a measure was under discussion, she said. Several options were being considered and China would choose policies in accordance with its conditions and stage of development.

"Our understanding of the word 'cap' is different from developed countries," Sun told a conference.

09 June 2014

In 1933, Richard Gray, a U.S. government weather forecaster, noted that Florida had been hit by at least 37 hurricanes over the 45 years ending in 1930. During this period, the longest stretch with no tropical storms was only two years.

When the 2014 hurricane season officially began on June 1, the Sunshine State had gone more than eight years without being struck by a hurricane. It was back on Oct. 24, 2005, when Hurricane Wilma emerged from the Gulf of Mexico and caused billions of dollars in damage in South Florida. In fact, Wilma was the last Category 3 or stronger storm to hit the USA.

The 3,151 days and counting with no Florida hurricane and no major U.S. hurricane shatters the previous records for hurricane "droughts," at least back to the turn of the previous century. In fact, from 1900 through 2013, the United States experienced a decrease in hurricane landfalls of more than 20%, and the strength of each year's landfalling storms has also decreased by more than 20%.

The figures at the top of this post show the data from 1900 to 2013 on landfalls (data from NOAA here) and the intensity of storms at landfall (data from NOAA updated from here, courtesy of C. Landsea, NHC). Since 1900 US hurricane seasons have seen more than 20% less landfalls and are more than 20% less intense. In my piece I defer to the IPCC on the emotive topic of hurricanes and climate change.

The main point of the piece is that we shouldn't let the past 9 years of abnormally low hurricane activity lull us into a sense of complacency. It is only a matter of time before the long streak with no US Cat 3+ and Florida hurricanes is broken.

05 June 2014

Paul Krugman, the Princeton professor, NY Times columnist and Nobel Prize winner, has put up a post today at the NYT in response to my letter in today's Financial Times. For years, Krugman has called me names and hid his critique behind vague allusions to my moral turpitude. In typical Krugman fashion he does that today too -- now I'm accused of pretending to hold views that I don't. Um, OK.

But let's set the drama aside and look at some data and analyses, because for the first time Krugman has engaged the substance of one of my arguments. And what he displays does not reflect well on his understanding of the nature of carbon dioxide emissions. So let's look at these issues in some detail.

The Kaya Identity is the centerpiece of the analyses found in The Climate Fix and a lot of my work. It is a very powerful tool for understanding the challenge of emissions reductions. It holds that carbon dioxide emissions are influenced by four factors:

population

GDP per capita

energy intensity of the economy

carbon intensity of energy

As an identity, it is expressed --> CO2 = P * GDP/P * E/GDP * CO2/E

(where P is population and E is energy consumption).

Now, the combination of population and per capita GDP is just GDP. Energy intensity reflects technologies of energy consumption (like cars and buses) and carbon intensity reflects technologies of energy production (like power plants and solar panels). Often it is useful to combine EI and CI into a metric of CO2/GDP, or the "carbon intensity of the economy."

The math here is simple. Increases in GDP, all else equal, mean that CO2 emissions go up. Improvements in technology (that is decreases in EI or CI) mean (all else equal) that CO2 emissions go down. Thus, we have two big levers with which to affect emissions - (a) GDP and (b) technologies of energy consumption and production.

Since my letter to the FT was about proposed hard caps on total CO2 emissions in China, let's illustrate the Kaya Identity with data from China (from 2011, where I find the most recent data).

Using the Kaya Identity in crude fashion tells us that China's CO2 emissions should have increased by ~8.1% in 2011 (that is 11.1 - [0.6+2.4]). Data from EIA shows an increase of just under 9%. So very close.

In order for China to "cap" CO2 emissions would require that the GDP growth rate equal the combined reductions in EI and CI. This can be achieved in two ways.

by bringing GDP down

by accelerating decreases in EI and/or CI

I have long argued that policies designed to purposely reduce economic growth by any meaningful amount are just not going to happen. On this point Krugman would seem to agree. But he also seems to think that increasing the combined rates of EI and CI to 9% per year can be achieved by pricing or some sort of voodoo. It can't because the needed price to achive such drastic rates of decarbonization would impact economic growth. Hence, the iron law.

To emphasize, placing a "cap" on emissions means that EI and CI together must total to the GDP growth rate. For emissions to be reduced, they have to exceed the GDP growth rate. The math here is as simple as it is inevitable.

I explained this in the FT today:

Thus, by definition, a “carbon cap” necessarily means that a government is committing to either a cessation of economic growth or to the systematic advancement of technological innovation in energy systems on a predictable schedule, such that economic growth is not constrained. Because halting economic growth is not an option, in China or anywhere else, and because technological innovation does not occur via fiat, there is in practice no such thing as a carbon cap.

In his response, Krugman displays both a lack of reading comprehension, and utter ignorance of the Kaya Identity, when he translates this as:

Wrong. I clearly explained the logic of the KayaIdentity as I have many, many times, and it has levers beyond economic growth. Strike one.

Krugman also seems to think that my letter has something to do with Obama's power plant regulations:

Still, the power plant policy is what’s in the news and motivate Pielke’s letter.

Wrong again, Paul. The letter was motivated by China's mythical "carbon caps" and in fact was written well before the EPA proposal was even on the table. Here is what I wrote earlier this week about the EPA regulations:

First, lest there be any confusion, I support the regulations and hope that they are implemented.

Wrong again. Strike two.

Krugman keeps it up:

Even more important, there are many ways to generate electricity: coal, gas, nuclear, hydro, wind, solar — and the alternatives to coal are more competitive than ever before. That doesn’t mean that reducing emissions has no cost — but again, the idea that, say, a 30 percent fall in emissions requires a 30 percent fall in GDP is ludicrous.

Indeed, it would be ludicrous had anyone actually said that. I certainly didn't. Strike three.

What we can do is use the Kaya Identity to quantify, for various assumptions of improvements in energy intensity of GDP (e.g., via efficiency gains) how much carbon-free energy needs to be deployed in order to hit a specific concentration target for CO2 emissions.

To achieve stabilization at a 2°C warming, we would need to install ~900 ± 500 MW [mega-watts] of carbon emissions-free power generating capacity each day over the next 50 years. This is roughly the equivalent of a large carbon emissions-free power plant becoming functional somewhere in the world every day. In many scenarios, this pace accelerates after mid-century. . . even stabilization at a 4°C warming would require installation of 410 MW of carbon emissions-free energy capacity each day.

Get that? A nuclear power plant-worth of carbon-free energy per day, every day until 2050. How's that rate of deployment coming Paul?

I'd love to see Krugman's alternative math here -- for hitting a China emissions "cap" or for stabilizing carbon dioxide at a low level. Krugman is very good at calling me names. His analysis of carbon emissions not so much.

03 June 2014

The graph above shows the mix of US electricity sources for 2012 and for 2020 and 2030 under the EPA carbon regulations which were proposed yesterday by the Obama Administration. (You can click on the graph for a bigger version). Sources can be found at the bottom.

Some points:

First, lest there be any confusion, I support the regulations and hope that they are implemented. My general views on using technology standards to stimulate innovation can be found, for example, here. I'd also encourage a close look at Japan's "Top Runner" programs.

The rhetoric surrounding the regulations is tempered by this data, on both sides.

If implemented, they would represent a significant reduction in coal generation from about 39% of the mix to about 33%, a drop of about 15% from total 2012 coal generation (and under different scenarios it could be a bit more or less). The US economy has already seen a larger reduction in coal electricity generation -- a 25% drop from 2005 to 2012 -- and the economy appears to have survived intact.

However, despite this reduction, the overall change to the US electricity mix is best characterized as marginal, rather than revolutionary. This is especially the case from 2020 to 2030 where there is very little projected change in the mix.

The so-called climate benefits of the regulations are thus essentially nil, though I suppose one could gin some up via creative but implausible cost-benefit analyses. Atmospheric carbon dioxide is a stock and flow problem and these proposed regulations make a only a very tiny contribution to the flow side of the equation. That is just math.

The US carbon regulations won't influence future extreme weather or its impacts in any detectable way. Hard to believe I felt compelled to write that.

The non-carbon public health benefits of decreased reliance on dirty coal are the most compelling reasons for the regulations, and they are considerable.

The bottom line is that the regulations are an important step to help motivate the electricity generating sector to move closer to the technological frontier. There will of course be winners and losers, and thus heavy politics. In addition, people love to fight about climate, and to use the climate debate as a political wedge as well as a sledgehammer for all sorts of interests. The proposed EPA regulations will be no different. The reality, at least with respect to the effect of the regulations on the energy sector, will be far more prosaic than the rhetoric.

Sources: EPA, 2014. Regulatory Impact Analysis for the Proposed Carbon Pollution Guidelines for Existing Power Plants and Emission Standards for Modified and Reconstructed Power Plants. Specifically, Panel 1, Table 2-2 here (PDF). Panels 2 and 3 are from the Option 1 (regional) scenario in Table 3-11 in the same source.